A terminal device connected with an electric wire on-site, such as a drive control device or a distribution board of industrial machinery as disclosed in Japanese Patent No. H10-155212A, has a quick connection terminal block. The electric wire is directly connected to a contact of the quick connection terminal block without the use of a crimp terminal or the like. The terminal block of JP H10-155212A has a slot into which an end of a stripped electric wire is inserted and a spring member for connecting the end of the electric wire inserted into the slot to a contact. By pushing the end of the electric wire in the slot against an elastic force of the spring member, or inserting the end of the electric wire into the slot with the spring member elastically deformed by a tool for wire connection, the end of the electric wire is electrically connected to the contact and retained in the terminal block with the elastic force of the spring member. In another known terminal block, instead of the spring member, the terminal block has a movable member movable in an axial direction of a screw by tightening the screw to press the end of the electric wire to the contact.
An electrical connector disclosed in Japanese Patent No. 2015-523700A has a lock arm for catching a mating connector. In order to prevent the lock arm from being damaged, a protection wall is provided in the vicinity of the lock arm.
The terminal block of JP H10-155212A does not have a lock arm for catching a mating terminal mated to the terminal block. In JP H10-155212A, by contrast, because the terminal block equipped with the mechanism for directly connecting the electric wire requires a movable space allowing deformation of the spring member or displacement of the movable member, the terminal block is thicker in a direction of deformation of the spring member or displacement of the movable member than a terminal block using a crimp terminal. A mechanism accommodating portion of a housing for accommodating the direct wire connection mechanism protrudes in a direction of thickness with respect to a portion of the housing formed with a cavity for accommodating the contact.
If the terminal block with the direct wire connection mechanism had a lock arm for catching a mating terminal, the lock arm could be disposed on an opposite side in the direction of thickness of the housing where the direct wire connection mechanism is accommodated. The housing, however, would then bulge to both the sides in the direction of thickness and encompass a larger space.
Alternatively, in order to avoid an increase in the thickness of the housing, the lock arm could be disposed on the same side as the mechanism accommodating portion. If the lock arm is positioned in a dead space on the same side as the mechanical accommodating portion and in front of the mechanical accommodating portion, a direction of movement of a mold part for molding a back face side of the lock arm is set in a direction perpendicular to frontward and rearward directions in order to prevent the mold part from interfering with the mechanism accommodating portion. However, if the mold on the back face side of the lock arm moves in that direction, the protection wall cannot be molded in the vicinity of the lock arm. Therefore, if the lock arm and the protection wall are integrally molded with the housing of the quick connection type terminal block, the lock arm must be positioned on the opposite side in the direction of thickness to the mechanism accommodating portion. As described above, however, this leads to a terminal block with an undesirable overall thickness.